This standard is applicable to: a) coupling capacitors for power line carrier (PLC) systems on high voltage overhead power lines the power-frequency range being 15 Hz to 60 Hz and the carrier frequency range 30 kHz to 500 kHz; b) capacitor dividers or capacitor voltage transformers. Additional requirements for capacitor voltage transformers are given in the standard approved by GSO concerned with “Voltage transformers" (1); c) capacitors with one terminal either permanently earthed or at low voltage as used for overvoltage protection and other similar uses.